! File: 4719C.PROP ! Database: PEPDB ! Date: 22-FEB-1994:23:43:22 coverpage: title_1: MORPHOLOGY OF GALAXIES IN CLUSTERS AT Z = 0.5 - title_2: CYCLE 2 DD PROGRAM - CONT OF 2373 sci_cat: GALAXIES & CLUSTERS sci_subcat: GALAXY MORPHOLOGY proposal_for: GO/DD longterm: 2 cont_id: 2373 pi_fname: ALAN pi_lname: DRESSLER pi_inst: CARNEGIE OBSERVATORIES pi_country: USA pi_phone: 818-304-0245 hours_pri: 11.00 num_pri: 2 wf_pc: Y funds_amount: 138240 funds_length: 12 off_fname: JOHN off_lname: LIVELY off_title: DIR., ADMIN. & FIN. off_inst: CARNEGIE INSTITUTION OF WASHINGTON off_addr_1: 1530 P. ST., N.W. off_city: WASHINGTON off_state: DC off_zip: 20005 off_country: USA off_phone: 202-387-6400 ! end of coverpage abstract: line_1: We outline a continuing program to study galaxy evolution through the line_2: investigation of galaxy morphology as a function of lookback time. The line_3: development of disks and bulges, the role of mergers, interactions, and other line_4: environmental influences, are expected to be visible over the range 0 < z < 1 line_5: as judged by the spectrophotometric evolution already observed over this line_6: redshift range. In this Cycle 2 we propose WFC imaging of one new field, line_7: the rich cluster A370 at z = 0.37, for which extensive photometry and line_8: already exist. Also, we will revisit a Cycle 1 target, the rich cluster line_9: CL0939+4713, for a 2-orbit exposure with the F555W filter to complement our line_10: 10-orbit exposure in F702W. This will be our first attempt to obtain limited line_11: color information to help interpret the morphological classifications we are line_12: engaged in. In general, all these data will be used primarily to classify line_13: images according to traditional morphological categories and will be used, line_14: within the constraints implied by deconvolution techniques, to measure surface line_15: brightness distributions and bulge-to-disk ratios. A brief description is line_16: given of how the data are applicable to specific questions, like the line_17: cause of enhanced starburst activity found for high-z galaxies. ! ! end of abstract general_form_proposers: lname: DRESSLER fname: ALAN title: P.I. inst: CARNEGIE OBSERVATORIES country: USA ! lname: BUTCHER fname: HARVEY inst: KAPTEYN OBSERVATORY country: NETHERLANDS esa: Y ! lname: OEMLER fname: AUGUSTUS, JR. inst: DEPARTMENT OF ASTRONOMY, YALE U. country: USA ! ! end of general_form_proposers block general_form_text: question: 3 section: 1 line_1: Our original plan was to use the WFC to image 2 fields in line_2: each of 8 clusters 0.36 < z < 0.55 over a period of 2 line_3: years, fields selected from ground-based CCD images. For line_4: each cluster, multicolor photometry for several hundred line_5: objects, and low-resolution spectra for 30-50 representative line_6: galaxies in the fields covering a magnitude range 19 < line_7: m(r) < 23, are available. These fields typically contain line_8: field/cluster galaxies in the ratio of 1/2, so the sample line_9: covers a wide range of environments. Spectra have been line_10: classified according to "activity", as described in the text line_11: and the papers cited. The field centers were chosen to line_12: maximize the number of "active" galaxies. line_14: Following the discovery of SA in the HST-OTA, we requested line_15: (and received) 11 hours from our original allocation of 28.5 line_16: to image a single cluster (CL0024+1654) in one color. This line_17: observation was intended to test the recovery of line_18: morphological information on high-redshift galaxies given line_19: the degraded imaging performance. We analyzed 3 hours line_20: of exposure of these data and concluded that, because of the line_21: small core of the PSF, salient features of morphological line_22: classification can be extracted with of order 6 hours or line_23: greater exposure on clusters at z = 0.4. ! question: 3 section: 2 line_1: With our remaining time in Cycle 1, we obtained an exposure line_2: of approximately 6 hours on a second cluster CL0939+4713. line_3: With the additional 11 hours allocated for Cycle 2, we line_4: will increase the integration on CL0024+1654 and add a new line_5: cluster CL1446+2621. In this DD proposal of 8 hours we are line_6: adding an 8-orbit exposure on the rich cluster A370. These line_7: exposures will be coadded from single-orbit exposures, done line_8: in a single color with filter F702W, which roughly corresponds line_9: to a rest-frame color between B and V. Information on color line_10: distributions formed a promising part of our original observing line_11: plan, but we were uncertain about ability to restore images of line_12: sufficient photometric accuracy through deconvolution. However, line_13: our subsequent experience with the LUCY algorithm has convinced line_14: us that we should explore the usefulness of multi-color data line_15: and test to what extent our conclusions on morphology are color line_16: dependent. Hence, this proposal includes a 2-orbit exposure line_17: with F555W (rest frame U) on one of our Cycle 1 targets, line_18: CL0939+4713. It is important that these additional data on line_19: CL0939+4713 be taken at the SAME ORIENT as the original F702W line_20: exposures. Also, it is essential that our exposures on A370 be line_21: done over a 7 day period in order to deliver the SAME ORIENT so line_22: that the frames may be coadded. ! question: 4 section: 1 line_1: For our original proposal we used CCD images of low-z line_2: cluster spirals to simulate HST observations and concluded line_3: that 20,000 s (8 x 2500 s single-orbit) exposures were line_4: desireable for satisfactory classification. We have obtained line_5: CCD images of spiral galaxies in a low-redshift cluster and line_6: used them to simulate exposures with the WFC, taking into line_7: account telescope and detector efficiency, dark current, line_8: readout noise, resolution, and sampling. line_10: From our 5 orbits of data on Cl0024+1654 (Cycle 1), and line_11: 10 orbits on CL0939+4713, we demonstrated that useful line_12: morphological data can be extracted, even with the SA line_13: problem, thanks to the significant power in the core of line_14: the PSF. In these data we clearly see thin disks and line_15: and unresolved point-like structures in galaxies with line_16: V = 21. line_17: We have chosen not to pursue even better S/N ratio data, line_18: but rather to use the balance of our time to image 2 other line_19: clusters (and to increase the exposure on CL0024+1654), so line_20: that we will have roughly 5 hours for each of 4 fields, line_21: thereby covering the minimum range of environments. ! question: 5 section: 1 line_1: Do all exposures PER TARGET within 7 days in this program. line_2: For the first set, do the following: line_3: Do all exposures within 7 days. Exposure line 1 should be line_4: done first according to SPB, and the multiple exposures in line_5: lines 2 and 3 can follow as schedulable. The exposures in line_6: exposure log lines 1 and 2 are all to be done at POS TARG line_7: +10,-10 and those in exposure log line 3 are all to be done at line_8: POS TARG +11,-8. The SAME ORIENT should be used for all of the line_9: exposures in lines 1-3. line_10: Similar instructions apply to the next set of lines: line_11: The exposures in lines 4 and 5 can be done as schedulable line_12: within 7 days. The exposure in exposure log line 4 is to be line_13: done at POS TARG +10,-10 and the one in exposure log line 5 is line_14: to be done at POS TARG +11,-8. The SAME ORIENT should be used line_15: for both of the exposures in lines 4-5. line_16: NOTE: In the discussion above, and on the exposure logsheet line_17: lines, POS TARG +10,-10 is intended to roughly duplicate the line_18: old POS TARG 0,0 used in the Cycle 1 versions of this program, line_19: and POS TARG +11,-8 is intended to roughly duplicate the old line_20: Cycle 1 usage, POS TARG 1,2. These changes were made because line_21: the STScI redefined the coordinate system and apertures for line_22: the WF/PC. The aperture WFALL-FIX is used to tie the aperture line_23: center to the same reference point over time in case the ! question: 5 section: 2 line_1: WFALL aperture center location is shifted for any reason by line_2: STScI. line_3: ALSO, NOTE THE FOLLOWING: There is a specific ORIENT line_4: angle requested for the exposures of the second target, line_5: GAL-CLUS-093942+4713-FLD1 ( Exposure Log lines 4-5 ), with line_6: the angle being specified in the special requirements on line_7: Exposure Log line 4. So, there is both a specific ORIENT line_8: requirement for this target, and a requirement that all line_9: other data for it be taken at the SAME ORIENT. This is line_10: being done to match data in a different filter which was line_11: done in Proposal 4014. Specifically, the U3 ORIENT angle for line_12: the special requirement on Exp Log line 4 is 137.32D, and line_13: this is intended to match the ORIENT used in SUs 01 and 02 line_14: of GO 4014. This also corresponds to the V3 Position Angle line_15: of 317.32 used in 4014. line_16: ( V3 POS ANGLE - 180D = U3 ORIENT angle for special reqs. ) line_17: So, 317.32D - 180D = 137.32D = ORIENT for Exp Log lines 4-5. line_18: Note, however, that in this proposal, the coords for Cl 0939 line_19: have been moved 9 arcsec North of those used in GO 4014, line_20: at the request of the PI. ! question: 7 section: 1 line_1: In order to accomplish our scientific objectives line_2: we must develop methods of moving from images to line_3: parametrized data. Traditionally this has been accomplished line_4: by using the image processing capabilities of the human eye line_5: plus brain, in order to assign morphological classes, line_6: estimate bulge-to-disk ratios, and describe distributions of line_7: color, dust, non-axisymmetric structures, etc. These line_8: classifications are semi-quantitative at best, and useful line_9: results regarding the evolution of galaxy morphology will line_10: depend on having an equivalent sample of observations at low line_11: redshift for which the same subjective criteria can be line_12: applied. With this in mind, Dressler has begun to line_13: obtain CCD images of low redshift clusters 0.02 < z < 0.04 line_14: in seeing of FWHM < 1 arcsecond. With suitable processing, line_15: such data can be used to simulate the HST observations line_16: (similar sampling, S/N, and resolution) in order to provide line_17: calibration images. Thus, although the criteria will line_18: remain subjective in this initial step, it can be applied so line_19: that redshift is the only significant variable, and a good line_20: assessment of differential morphology can be made. Our early line_21: comparison of our first HST images to convolved ground-based line_22: images for low-redshift confirms this approach as instructive line_23: in assessing morphology, even with the SA problem. ! question: 7 section: 2 line_1: With the point spread functions we obtained with our line_2: most recent data on CL0939+4713, we were highly successful line_3: in deconvolving the images with the LUCY algorithm. This line_4: had the primary effect of removing the scattered light of line_5: the PSF halos (due to spherical aberration) which were line_6: hampering somewhat our efforts at morhpological line_7: classification. ! question: 9 section: 1 line_1: We are presently involved in analyzing our first WFC images, line_2: of cluster CL0024+1654 and CL0939+4713, as described in the line_3: above text. ! question: 10 section: 1 line_1: Dressler and Oemler each have access to a MicroVAX line_2: computer with image display capability. Each MicroVAX is line_3: part of a VAX system, supplied and maintained individually line_4: by MWLCO and Yale which includes a variety of line_5: I/O devices and access to BITNET and other communication line_6: networks. Both now also have and are using SUN line_7: workstations to process and analyze the WFC data. ! !end of general form text general_form_address: lname: DRESSLER fname: ALAN category: PI inst: CARNEGIE OBSERVATORIES addr_1: 813 SANTA BARBARA ST. city: PASADENA state: CA zip: 91101 country: USA phone: 818-304-0245 ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: GAL-CLUS-ABELL370-FLD1A descr_1: F,404,411 pos_1: RA= 02H37M21.3S +/-0.1S, pos_2: DEC= -01D47'15.5" +/-1" equinox: 1950.0 rv_or_z: Z=0.37 ! targnum: 2 name_1: GAL-CLUS-093942+4713-FLD1 descr_1: F,404 pos_1: RA= 09H39M48.0S +/-0.1S, pos_2: DEC= +47D12'30.0" +/-1" equinox: 1950.0 rv_or_z: Z=0.40 comment_1: COORDS ARE 9 ARCSEC NORTH comment_2: OF THOSE USED IN GO 4014. ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.000 targname: GAL-CLUS-ABELL370-FLD1A config: WFC opmode: IMAGE aperture: WFALL-FIX sp_element: F702W num_exp: 1 time_per_exp: 2100S priority: 1 param_1: CR-SPLIT=NO, param_2: PRE-FLASH=NO req_1: CYCLE 2 / 1-3; req_2: POS TARG +10,-10; req_3: GROUP 1-3 WITHIN 7D; req_4: SAME ORIENT FOR 2-3 AS 1; ! linenum: 2.000 targname: GAL-CLUS-ABELL370-FLD1A config: WFC opmode: IMAGE aperture: WFALL-FIX sp_element: F702W num_exp: 3 time_per_exp: 2200S priority: 1 param_1: CR-SPLIT=NO, param_2: PRE-FLASH=NO req_1: POS TARG +10,-10; ! linenum: 3.000 targname: GAL-CLUS-ABELL370-FLD1A config: WFC opmode: IMAGE aperture: WFALL-FIX sp_element: F702W num_exp: 4 time_per_exp: 2200S priority: 1 param_1: CR-SPLIT=NO, param_2: PRE-FLASH=NO req_1: POS TARG +11,-8; comment_1: OFFSET 1 ARCSEC IN RA AND 2 ARCSEC IN comment_2: DEC TO REMOVE POSSIBLE EFFECTS comment_3: ASSOCIATED WITH INDIVIDUAL PIXELS AND comment_4: POINT SPREAD FUNCTIONS. ! linenum: 4.000 targname: GAL-CLUS-093942+4713-FLD1 config: WFC opmode: IMAGE aperture: WFALL-FIX sp_element: F555W num_exp: 1 time_per_exp: 2000S priority: 1 param_1: CR-SPLIT=0.5, param_2: CR-TOLERANCE=0.0, param_3: PRE-FLASH=NO req_1: CYCLE 2 / 4-5; req_2: POS TARG +10,-10; req_3: GROUP 4-5 WITHIN 7D; req_4: ORIENT 137.32D +/- 0.01D; req_5: SAME ORIENT FOR 5 AS 4; comment_1: THIS ORIENT IS INTENDED TO DUPLICATE comment_2: THE ORIENT USED IN SU 01 AND 02 OF comment_3: GO 4014, AND CORRESPONDS TO A comment_4: V3 POS ANGLE OF 317.32. comment_5: TARGET POSITION IS 9 ARCSEC comment_6: NORTH OF THAT USED IN GO 4014. ! linenum: 5.000 targname: GAL-CLUS-093942+4713-FLD1 config: WFC opmode: IMAGE aperture: WFALL-FIX sp_element: F555W num_exp: 1 time_per_exp: 2000S priority: 1 param_1: CR-SPLIT=0.5, param_2: CR-TOLERANCE=0.0, param_3: PRE-FLASH=NO req_1: POS TARG +11,-8; comment_1: OFFSET 1 ARCSEC IN RA AND 2 ARCSEC IN comment_2: DEC TO REMOVE POSSIBLE EFFECTS comment_3: ASSOCIATED WITH INDIVIDUAL PIXELS AND comment_4: POINT SPREAD FUNCTIONS. MUST BE DONE comment_5: AT SAME ORIENT AS EXP LOG LINE 4, comment_6: ABOVE. ! ! end of exposure logsheet ! No scan data records found